You're assuming the employees stocked them on the wrong rack or mispriced them. Far more often, I believe, knucklehead shoppers grab those high dollar baits off the shelf, tote them around while considering whether or not to purchase them and then ultimately decide not to. Rather than return them to their high-dollar rack, they ditch them in the closest spot: the discount box.
I agree that this happens a lot more than it should, but there are usually ways to tell when this is the case. There will either be an orange sticker on all the true clearance merchandise and a few baits without them, or something just doesn't fit in with everything else, for example 4 crankbaits in a bin with 200 spinnerbaits and a big sign saying "brand x spinnerbaits 50% off."
The situation I am talking about happens more rarely, but I have seen it. In an aisle there will be several rows of an item on hooks which are labeled far below what I know to be retail for that item, so I grab a few thinking they are on sale, only to have them ring up full price. This is when I tell the person working the register the price that it was advertised for on the rack, and if need be show them where I got the item. If it turns out the item was stocked incorrectly, sometimes they honor the price and sometimes they don't like RW said. If they don't and I don't want to pay retail, I say thanks anyway and leave it there. If they do honor it though, I have no problem taking advantage of the deal.